The state of the art in poultry processing tools is currently characterized by the use of a conventional scissors to snip away undesirable pieces of cartilage, tendons, broken bones, etc. The lower blade of the conventional scissor, however, is operated by the thumb and the upper blade is controlled by the user's index and middle finger, the latter two (2) fingers extending at substantially right angles to the palm of the user's hand and the thumb extending at a 60.degree.-80.degree. angle to the flat of the palm. This angled relationship is frequently the cause of what is known in the poultry industry as the "carpal tunnel syndrome" which develops in the wrist of most workers who perform this type of work regularly over a span of several years.
The "carpal tunnel syndrome" is evidenced in the area of the carpal tunnel of the user by inflammation, swelling, and pain, and eventually incapacitates the user for that type of work. The carpal tunnel is an area at the inner side of the human wrist through which a nerve runs to the hand and which frequently is a cause of trouble for people who utilize their hands and fingers a great deal, such as pianists, typists, fabric manufacturing workers, knitters, tennis players, poultry processors, etc. Such excess activity may cause tissue to develop in the area of that nerve adjacent the base of the hand. Substantial development of such tissue brings pressure to bear upon that nerve, with resultant inflammation and pain. Relief is obtained primarily by surgery in which the excess tissue is cut away and removed, so as to alleviate the pressure upon the nerve and terminate the pain caused thereby. Such surgery is both expensive and painful and, in addition, incapacitates the worker for a substantial period of time. Moreover, the patient is well-advised to cease that type of employment rather than to risk further complications and redevelopment of more of such objectionable tissue.
In the center of the human wrist, bones and a ligament form a narrow tunnel containing tendons and a major nerve, called the median nerve. The median nerve conducts sensations from the hand, up the arm, to the central nervous system. When the nerve is compressed at the wrist, the hand and fingers are affected adversely. The synovium around the tendons may become thick and sticky due to the normal wear and tear of the aging process or repetitive hand movements, thus pressing the nerve against the tunnel. Various conditions may cause wrist structures to take up extra space in the carpal tunnel. Since bones and ligaments are not compressible, this puts pressure on the nerve, resulting in the symptoms known as "carpal tunnel syndrome".
The "carpal tunnel syndrome" is caused by compression of the median nerve between the substantially inelastic carpal ligament and other structures within the carpal tunnel. The volume of the contents of the tunnel can be increased by organic lesions such as synovitis of the tendon sheathes. Even though no anatomic lesion may be apparent, flattening or even circumferential constriction of the median nerve may be observed during operative action of the ligament. Symptoms of carpal tunnel syndrome occur in the hands and fingers and evidences itself as numbness, tingling, and burning sensations, "pins and needles", and pain in the middle and index fingers and thumb, and sometimes in all five fingers.
Poultry processors normally work with the scissors in wide-open position for maximum purchase in the cutting operation. That position maximizes the angle of the thumb to the palm of the hand and to the area called the carpal tunnel area, thus substantially increasing the likelihood of the development of the objectionable tissue in the carpal tunnel area, as described above. It can be seen that the flesh of the thumb approaches and retracts from the carpal tunnel area as a scissor is manipulated in such a manner and position, to thereby facilitate the development of such undesirable tissue. The repetitive movements of the fingers required of such poultry processors lead to the development of the "carpal tunnel syndrome" in many of them.
My invention is directed toward obviating, or at least greatly minimizing, the tendency for the development of the "carpal tunnel syndrome" by poultry processing workers engaged in such activities.